Certain food processing operations require adding processing fluids to a foodstuff. U.S. Pat. No. 5,871,795, for example, discloses a method using ammonia and/or carbon dioxide to modify the pH of a meat product. The treatment disclosed in U.S. Pat. No. 5,871,795 has been shown to decrease pathogenic microbe content in meat products. U.S. Pat. No. 6,389,838 also discloses a process in which a pH modifying material such as gaseous or aqueous ammonia is applied to meat products as part of an overall process that includes freezing and physically manipulating the pH modified meat product.
Treatment processes that expose foodstuffs to a processing fluid may require a controlled and consistent application of the processing fluid. Depending upon the treatment process, underexposure may not provide the desired results, while overexposure to the processing fluid may produce undesirable results. In the pH adjustment processes described in U.S. Pat. Nos. 5,871,795 and 6,389,838 for example, portions of the meat product being treated may be overexposed to the pH adjusting fluid while other portions of the meat product may be exposed to very little or none of the pH adjusting fluid. The overexposed portions may absorb sufficient adjusting fluid to affect the taste of the treated product and to produce a residual pH adjusting material odor. Underexposed portions of the meat product may not exhibit the desired pathogenic microbe inhibiting effect.